


Affection

by hyliank8



Category: Undertale (Video Game)
Genre: Fluff, Kissing, M/M, Praise Kink, Size Difference, Sweet Sex, W. D. Gaster is not related to Skelebros, head pets, safe for angst-free diets, soft
Language: English
Status: Completed
Published: 2020-10-12
Updated: 2020-10-12
Packaged: 2021-03-08 04:02:31
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 446
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26979289
Author URL: https://archiveofourown.org/users/hyliank8/pseuds/hyliank8
Summary: Gaster is gentle with Sans.
Relationships: W. D. Gaster/Sans
Comments: 10
Kudos: 59





	Affection

**Author's Note:**

> i jus wanted 2 write gaster giving sans smol head pets as they're intimate, that is why this exists. credit to [@cycopasu on tumblr](https://www.tumblr.com/blog/view/cycopasu) for this idea bc i lov it and i'm dying bc they're so soft and love each other so much,
> 
> the original idea was head pat and this is more of a head pet so Slight Difference i suppose buT u kno whaT its ok they love each other tht's the point

“Such a sweet boy... look at you, so small and precious...”

Sans groans at the words spoken into the crook of his neck, Gaster’s hot breath against him sending heat straight to his core. Gaster rocks into him slowly, gently, taking his sweet time building the pleasure between them. He summons one of his extra hands to cup Sans’ cheekbone delicately, and Sans closes his eyes and tilts his head to the side, leaning into the soft touch.

“You’re so perfect...” Gaster murmurs against the side of his skull. “I could do this all night, you know that? I could make love to you forever.”

“ ‘dings...” Sans can’t help the heat that rushes to his face at that, at the untempered _love_ laced in Gaster’s words. His soul is warm with affection for his lover, and being joined with him like this is one of the most comfortable feelings in the world. Gaster materializes another extra hand and places it on the top of Sans’ head, delicately stroking his fingers over his partner’s skull in a slow, soothing motion as he continues his gentle thrusts.

“It’s true,” Gaster continues seamlessly. “You’re so good, so wonderful...”

Stars, the praise, the _sincerity_ in his words... Sans sighs and tilts his head up into the tender contact on the top of his skull. He’s certain he’s never felt so good in his entire life.

On his next thrust, Gaster rocks into him a little harder, but he takes extra care to keep the methodical touches over Sans’ skull slow and light. The contrasting sensations are almost overwhelming for Sans—they’re such different intensities but they’re both so _good_.

“I love you more than anything, Sans.”

Sans’ soul flutters at that, the pleasure in his gut coiling tighter. “ _hnn,_ i-i... i love you too, gaster,” he gasps. “f-fuck, i’m g-gonna...”

“Good boy, Sans; come on... let go and come for me.”

Sans cries out as he reaches his peak, shuddering with the intensity of his release. Gaster continues his gentle thrusts, riding him through his orgasm until he hears the slight hitch to Sans’ breath that always indicates that he’s on the verge of overstimulation. 

Gaster stills his hips, careful not to overwhelm his lover, and places a soft kiss on Sans’ cheekbone. He continues caressing the top of his head as he listens to Sans’ breathing slow and his soulbeat begin to calm nearer to its resting thrum.

“You did so well, my sweetheart,” Gaster says quietly. “Did that feel good for you?”

“god, y-yeah,” Sans manages, still breathless.

Gaster smiles. “Good.”

As Gaster pulls him into a deep kiss, Sans reflects that he wouldn’t mind another round, either.

**Author's Note:**

> i kno this is short and kinda not edited that well, i'm workin on other stuff that hopefully i can have out sometime after my exam week is done
> 
> pls feel free 2 join me in sanster hell on [tumblr](https://hyliantimelordin221b.tumblr.com/) or [twitter](https://twitter.com/K8Maybe) or [elsewhere](https://hyliank8.carrd.co/)
> 
> if u comment i lov u


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